Study On Optimal Allocation Of Urban Water Resources In Arid Area

With the continuous advancement of urbanization,the contradiction between the shortage of available water resources and social development is becoming more and more acute.As a typical arid area in China,the central urban area of Ordos has been t hreatened by the damage of regional economic development to water sources in recent years.Therefore,the optimal allocation of water resources in the central urban area of Ordos is studied.This study not only provides reference for decision-makers to formu late water resources management policies,but also provides a theoretical basis for urb an water resources management in arid areas.Taking the central urban area of Ordos a s the research area,this paper selects 2018 as the current year and 2025 and 2030 as th e near and medium-term planning years;Based on the analysis of water supply and de mand and balance in the planning year,the optimal allocation scheme of water resour ces in the planning year of the study area is finally obtained by using WEAP model.T he main research contents and results are as follows:(1)Water demand prediction:through the water consumption data of the study ar ea,a combined prediction model is constructed based on Grey GM(1,1)and BP artifi cial neural network to calculate the planned annual water demand of the study area.T he prediction results show that the prediction accuracy of the combined prediction mo del is the highest compared with grey GM(1,1)and BP artificial neural network;Fina lly,it is calculated that the domestic water demand in 2025 and 2030 is 49.93 million m~3and 72.48 million m~3respectively,the water demand of the secondary industry is57.47 million m~3and 65.62 million m~3respectively,and the water demand of the terti ary industry is 11.22 million m~3and 16.66 million m~3respectively.(2)Analysis of available water supply:According to the existing data,the water s upply sources in the central urban area of Ordos are composed of groundwater,reclai med water and drained water.Based on the basic conditions of each water supply sour ce and water resource configuration file,the available water supply volume of each w ater supply source in the study area in the planning year is finally obtained.In the plan ning year 2025 and 2030,the available water supply of groundwater in the study area will be 169 thousand m~3/d,182 thousand m~3/d respectively;The reclaimed water is114.2 thousand m~3/d?115.7 thousand m~3/d respectively;The drain ed water is 135.6 thousand m~3/d?160.3 thousand m~3/d respectively;The total amount of available water supply in the study area is 416.8 thousand m~3/d and 498 thousand m~3/d respecti vely.(3)Research on optimal allocation of water resources:after analyzing the balanc e between supply and demand in the planning year of the research area and knowing t hat the future water demand of the research area cannot be fully met,the research on o ptimal allocation of water resources in the research area is started.Firstly,the WEAP model is used to construct the regional water resources allocation system and analyze its feasibility.Then,ten combined water resources allocation plans based on three fact ors:different development modes,water management policies and water supply proje cts are established.Finally,the comprehensive benefit evaluation value of each combi ned plan based on social and economic benefit results is obtained by Z-score and AHP methods.The results show that the comprehensive benefit evaluation value of"rapid development-strong water saving-increasing mining capacity"is the highest.Accor ding to this water resources allocation plan,the GDP will reach 296.572 billion yuan a nd 496.068 billion yuan respectively in 2025 and 2030;The water shortage rate is 0%and 0.3%respectively,and the realization of this plan requires a total investment of 1.971 billion yuan for the construction of water supply projects in the planning year.